Multi-cylinder pump



Oct. 6, 1964 M. P. H. scHLANzKY ETAL 3,151g561 MULTI-CYLINDER PUMP Filed Dec. l, 1961 INVENTORS.

United States Patent "i 3,151,561 MULTl-CYLHNDER PUMP l Manfred P. H. Schlanzky and Joseph G. Zubaty, Flint,

Mich., assigner-s to General Motors Corporation, Detroit, Mich., a corporation of Delaware Filed Dec. 1, 1961, Ser. No. 156,461 1 Claim. (Cl. 19E- 37) This invention relates to pumps and more particularly to pumps of the multi-cylinder type which preferably include wobble plate operated pumping elements.

In pumping liquids and particularly in handling fluids which are volatile, it is desirable to control the pump dis charge pressure without churning the fluid or dropping the pressure of any of the fluid already pressurized. lf gas oline, for example, is discharged at a pressure which is subsequently reduced by returning gasoline to the intake of the pump, churning in combination with the pressure drop will result to such an extent that vapor formation is encouraged. This gasoline return tends toward vapor formation because of the pressure drop alone although it be assumed that churning were somehow avoided. lt has now been found in practicing the present invention that much churning of the fluids being pumped can be avoided and depressurlzing to pump inlet pressure are effects which are ,not necessary in achieving automatic pump pressure discharge regulation in a multi-plunger pump.

To this end, an object of the present invention is to provide an improved multi-cylinder pump in which pressure regulation may be achieved with a minimum of churning of liquid being handled. Another object is to provide a multi-cylinder type of liquid pump in which depressurizing of any substantial quantity of the pump discharge iluid is substantially eliminated as a factor in controlling the discharge pressure.

A feature of the present invention is a multi-cylinder pump provided with valve means for automatically ccnnecting the discharge portions of the pump cylinders upon the attainment of a predetermined pump discharge pressure. Another feature is a pump having multiple cylinders adapted to effect sequential discharges through corresponding discharge valves to a common discharge passage or chamber until a predetermined pressure in the latter is attained, this arrangement being in combination with spring and pressure ac uated valve means giving communication between the cylinders when that pressure is reached for exceeded, the result being automatic regulation of the pump discharge pressure.

These and other important features of the invention will now be described in detail in the specification and then pointed out more particularly in the appended claims.

The drawing shows an elevation view of a fuel pump as one embodiment of the present invention, a major portion being in section in two planes better to illustrate the construction. lt will be appreciated as the description proceeds that although plungers `are disclosed as the preferred pumping elements for applying pressure to the fluid, the invention may also be utilized with the use of diaphragms such as are disclosed in the United States Patent 2,991,723, granted July ll, 1961, in the name of Joseph Zubaty. The use of diaphragm or plungers as pumping elements are disclosed in the United States Patent 2,955,475, granted October ll, 196i), also in the name of loseph Zubaty. Also, the pumping elements may be operated sequentially by cam action derived from a driver mechanism other than a wobble plate although the latter is preferred.

ln the drawing, the fuel pump is shown as including a multi-part body portion generally indicated at 10. This body portion includes a main body 12 defining a circular 3,151,561 Patented Oct. 6, 1964 series of cylinders such as the cylinders 14. A top body portion 16 is attached to :the main body portion 12 with a gasket 1d interposed. A bottom portion 20 is ixed to the underside of the main body 12 with a sealing gasket 22 interposed. These three parts making up the body portion 1S are held together by means of bolts such as the bolt 24.

Several of these bolts are utilized although not shown in the drawing and are placed around the main body portion 12.

The bottom body portion 2i) is not shown in detail but it will be appreciated that it is designed for the inclusion of a driving shaft 26 which is adapted to be driven by an electric motor or other power device. This shaft extends upwardly through the bottom body portion 20 into an inlet chamber 23. A threaded inlet 30 is formed in the bottom body pontion 2i? for the reception of an inlet connection and communicates with the inlet chamber 2S. T he latter is of such dimensions as to receive a wobble plate indicated at 32 which is keyed to the upper end of the shaft 26 for rotation therewith. Sealing means 34 and thrust bearing 36 are arranged with respect to the shaft 26 and the wobble plate 32 so that leakage from the chamber 23 down into the bottom body portion 20 is avoided. Details regarding the wobble plate 32 and its particular mode of mounting or sealing are not given herein as they form no part of the present invention.

The main body portion 12 is provided with plungers such as the plungers 38 and which are reciprocable in the cylinders 14. These plungers are similar in that each one bears a central passage 4u having an oblique inlet passage 42 leading to the chamber 28. Each plunger 38 is also provided with a valve element 44 which is adapted to seat upon the upper wall of the plunger to close the passage 46. An inverted and lianged cup 48 is retained on the plunger 33 by means of a coiled spring Si). The cup 4S is centrally apertured as at 52 and bears side openings 53. lt serves to limit valve lift.

The top body portion 16 bears an annular outlet chamber or groove 54 and this is connected with a vertically extended branch chamber 56 in turn in communication with a threaded outlet 58 adapted to be in connection with a discharge line. The main body portion 12 also has an opstanding central boss 60 which is bored to form a pressure chamber 62. Coaxial with this chamber 62 is a smaller diameter chamber 64 which extends downwardly through the portion 12 and communicates with the inlet chamber 2S. The annular groove 54 and its branch chamber 56 are in communication with the chamber 62 by means of a groove 66 formed in the top portion 16 and a small drilled opening or restrictive passage 68 which passes through the lower part of the wall of the boss 60.

A cylindrical slide valve generally indicated at 70 constitutes a unitary valve means and includes a reduced diameter portion 72, a lower portion of which is reciprocaole in the bore 64. It also includes an annular sleeve or cylindrical member 74 retained around the upper portion of the portion 72 and which is axially slidable in the chamber 62. At the upper end of the valve portion 72 is an enlargement 76. The cylindrical sleeve 74 is held tightly and in sealed relation with the enlarged portion 76 by means of a spring clip Sil and an O-ring 82 and presents a shoulder 75. Valve 'lil is provided with an annular groove 84 near its lower end. It is also provided with a vertical bypass port 86 which is reduced in diameter as shown at SS. Each cylinder 14 is provided with a vertical port 9@ which is controlled by a ball check valve 92 so that ow from the port 9i? may pass into the annular groove 54 by way of a radial port 94 when the corresponding plunger 3S develops sucient pressure in its pumping chamber 96. Each pumping chamber 96 is provided with .J an auxiliary port 9S leading to an intermediate zone of the chamber 64.

A cap member 100 bearing a spring chamber 102 therein is xed to the top pump body portion 16 by means not shown and leakage from between the two portions is prevented by an O-ring 104. The chamber 102 is coaxial with the valve means 70 and encloses a coil spring 106 which bears down on the valve member so that during pump discharge before the predetermined pump discharge pressure is developed, the annular passage 84 will be below and out of communication with the xed auxiliary ports 98.

Assuming that gasoline is admitted through the threaded inlet 30 to the chamber 2S and that the wobble plate 32 is rotated to Veieot a pumping action, the annular series of plungers 38 will reciprocate in sequential pumping cycles. During the upstroke of each plunger 38, the valve 44 will be closed and fuel will be pulled into the chamber 40 and during the downstroke of each plunger 38 that fuel will be caused 4to open the one-way Valve 44 and iiow into the pumping chamber 96 with the .check valve 92 closed. From chamber 96 during the subsequent upstroke the fluid will be forced up through the ball check valve 92 into therannular chamber 54 and out through the connection to the threaded outletl 58. Assuming that the latter is restricted by a carburetor or some other device requiring a given pressure of fluid to operate the plungers, the sequential action of lthe latter will continue to build up the pressure until eventually the predetermined pressure in the annular chamber 54 will be conveyed by way of the groove 66fand the restrictive outlet 68 into the pressure chamber 62 and will eXent itself with suicient force against theannular shoulder 75 to elevate the valve means 70 against the loading of the spring 106. \Vhen the predetermined discharge pressure has been reached, the

annular groove 84 will communicate with the portsr98 Awithout any substantial loss of pressure. The discharge pressure of the pump is determined by the loading placed upon the spring 106.

Cil

The bypass port 86 serves to return to the pump intake any gasoline which may leak past the valve 70 into the spring chamber 102. This has no relation to the operai A pump having a body portion forming a plurality of` cylinders in an annular series arrangement, pumping means in said cylinders and cooperating with the latter in defining pumping chambers, one-way inlet valve means connected to admit uid from a fluid supply source to said pumping chambers, means connected to said pumping means for reciprocating the latter in sequence, a discharge port in said body portion for each of said Vpumping chambers, a common dischargeY passage in said body portion leading from the discharge ports of said pumping chambers, one-way outlet valve means positioned to control the flow from each of said discharge ports to said common discharge passage, auxiliary ports in said body portion leading directly from said chambers and independent of said iiuid supply source, unitary valve means in said Y body portion and coaxial with said series of cylinders, said y body portion dening a restrictive passage connecting said common discharge passagerto said unitary valve means,

and the latter being controlled by pressure derived from said restrictive passage simultaneously to connect said auxiliary ponts whereby said fluid may flow directly from one of said pumping chambers to another when apredetermined pressure in said common discharge passage is effected.

References Cited in the tile of this patent UNITED STATES PATENTS 2,193,612 Alden Mar. 12, 19,40 2,501,054 Huber Mar. 2l, 1950 2,711,135 Eunlap June 21, 1955 2,792,789 Mizen May 21, 1957 2,940,396 Misulis `lune 14, 1960 Y 2,941,475 Blair lune 2l, 1960 Y 2,956,501 Norlin Oct. 18, 1960 3,002,528 Lerissner Oct. 3, 1961 

